Single exhaust port head gasket weep and left-side exhaust gas recirculation carbon plugging cause persistent overheating on regional station wagons. The Subaru Legacy Outback Forester Impreza EJ25E 2.5L H4 Engine terminates external coolant drips across this commercial long block repower. This 4-Cylinder 165HP boxer motor requires intake manifold coolant bypass pipe o-ring replacement before final torquing.

Cast A356-T6 aluminum forms the horizontally opposed crankcase featuring EJ25 top casting stamps and P25 cylinder heads. Centrifugal spun iron sleeves house coated hypereutectic pistons connected to a forged steel crankshaft rotating on tri-metal bearings. This Subaru engine core demands a 12V 145A starter draw during cold shop cranks. Total dry weight is 185 lbs, measuring 24in length, 28in width, 23in height, with a 4.5 quarts oil capacity.

Key Features of Subaru EJ25E Single Port

Fleet repair managers buy Subaru Legacy Outback Forester Impreza EJ25E 2.5L H4 Engine assemblies to eliminate repeat head gasket warranty comebacks. Our industrial engine rebuild standard uses upgraded multi layer steel head gaskets coated with high-temp fluoropolymer sealing layers.

- Cylinder bores measure 3.917in with diamond plateau hone cross-hatch patterns.
- Main bearing journal clearance holds at 0.0014in across the split-case aluminum block.
- Left cylinder heads incorporate dedicated California emissions exhaust gas recirculation passages.
- Single exhaust port casting design matches factory emissions downpipe configurations.
- Reinforced multi layer steel head gaskets eliminate external oil and coolant weeping.
- This EJ25E commercial core features cylinder head decks surfaced flat to 0.0003in.
- Stellite exhaust valve faces resist seat recession under sustained highway hauling.

Brake Dyno Performance Records

Automated brake cell test runs document that this EJ25E long block engine produces 165 continuous BHP and 166 ft-lbs of torque at 4000 continuous load RPM. Internal oil gallery pressure measures 54 PSI while oil sump temp remaining at 192°F under full load tests. Exhaust gas temp tops at 1260°F down the test exhaust runners. Compression pressures check between 178 PSI and 185 PSI across all four chambers. Crankshaft center journal runout holds within 0.0002in TIR.

Vehicle Application Mounting Scope

This powertrain configuration fits 2004 through 2005 Subaru Legacy sedans and Outback wagons built with California emissions packages. The block pairs with all-wheel-drive automatic or five-speed manual transaxles utilizing single exhaust port P25 or Z25P cylinder heads and left-head exhaust recirculation pipe unions.

Chassis Placement Setup Boundaries

Electronic throttle pedal return mechanisms demand 4 lbs of resistance force to confirm positive throttle plate closing at idle. This single exhaust port SOHC motor is not engineered for turbo performance builds, dual-port header platforms, marine craft, or aggregate rock crusher equipment.

- Drain initial break-in petroleum motor oil after 500 miles or 30 run hours.
- Inspect cold intake valve lash at 0.008in and exhaust lash at 0.010in.
- Torque cylinder head fasteners in six steps to 59 ft-lbs plus 90 degrees.

Commercial Protection Delivery Package

Backed by our rigorous Subaru assembly standard, this remanufactured motor carries a 3-Year 100,000-mile parts warranty. The wood crate houses the complete long block core, stamped steel oil pan, water pump, valve covers, oil pickup tube, and signed dynamometer test documentation.